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<title>Solubility diagrams (H+,CaCO3,CO2)</title>
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<p>A <b>solubility diagram</b> shows total dissolved concentrations
(on a logarithmic scale) usually plotted against a free concentration.
It is convenient to set the activity <nobr>= 1</nobr> for the solid phase of interest.
This can be done by <a href="S_Modify_Chem_System.htm">exchanging a component
for a reaction</a>, for example exchanging <nobr>Ca<sup>2+</sup></nobr> with
<nobr>CaCO<sub>3</sub>(s).</nobr></p>

<p>The following diagram shows the solubility of calcite in the system <nobr>H<sup>+</sup>,</nobr>
<nobr>CaCO<sub>3</sub>(s),</nobr> and <nobr>CO<sub>2</sub>(g)</nobr> at
<nobr>log&nbsp;<i>P</i><sub>CO<sub>2</sub></sub></nobr> = <nobr>&#8722;3.5:</nobr></p>
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<center><img src="images/Diagr_Solub.gif" border="1" width="307" height="215" alt="Solubility diagram"></center>
</p>

<p>This diagram was obtained with the following input file:</p>
<pre><code>3  8  1  1,
H+,CO2(g),CaCO3(s)
OH-     , -14.00 -1 0 0, HCO3- , -7.83 -1 1 0
H2CO3(aq), -1.48  0 1 0, CaOH+ , -3.12 1 -1 1
CaCO3(aq), -5.22  0 0 1, CaHCO3+, 2.91 1  0 1
CO3-2   , -18.16 -2 1 0, Ca+2  ,  9.74 2 -1 1
Ca(OH)2(s),-13.07 0 -1 1
ls,0,-7, H+,
lav,-5,-11,
la,-3.5,  la,0</code></pre>
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